Trying to catch up on various recent posts, though am a bit behind, so apologies. A few longer pieces have landed now as well. In the short term, here is something for my institutional home RUSI about what policy ideas could be advanced to manage the long-term threat that the UK faces.

A week after the atrocity in Manchester, it is now possible to draw some preliminary conclusions: there clearly was a breakdown in the intelligence flow that led to suicide bomber Salman Abedi slipping through the net; there are enduring questions about the UK’s Prevent anti-terrorism strategy; and, finally, there are the weaknesses of ‘soft targets’ that such an attack invariably expose.

It is, of course, impossible, without full access to information, to properly understand exactly the nature of the intelligence breakdown that led to last week’s suicide attack on an Ariana Grande concert in Manchester.

Still the fact that the bomber, Salman Abedi, was flagged up to authorities a number of times, by locals in Manchester, was travelling back and forth to a country that is a warzone and came from a family with strong militant pedigrees all indicate – without the benefit of hindsight – that he was someone who should have attracted attention.

If, as suggested, he was someone who had featured in previous investigations but was sidelined in favour of what were deemed to be more menacing targets, then the attack in which 22 people were killed and dozens wounded highlights what for the intelligence services remains a perennial question: how do you determine who seems more menacing when resources are limited?

This is not only a difficult calibration to make, it is also not a way to remove someone from concerns altogether. For, as we have seen repeatedly, individuals will sometimes rise back out of this pool of downgraded threats to pose an immediate danger.

And the challenge is immense. According to Security Minister Ben Wallace, there are about 20,000 in this larger pool of people who are not seen as an immediate danger but who, like Abedi, can suddenly become one.

What can be done to manage this problem? Additional resources would help, as well as new technologies such as super computers using artificial intelligence to manage the challenge through data-crunching looking for particular patterns of behaviour. Another method is to continually challenge previous assessments about the security risks that certain individuals may pose, a determination which is bound to shift over time.

However, the principle of proportionality also has to be borne in mind: having lots of security forces chasing those individuals not only requires more resources than are currently available, but may also end up exacerbating the very problem that they are trying to manage.

Other, more extreme ideas have been advanced: internment or enhanced restrictive movement orders. The first proposal is so clearly counterproductive that it bears no consideration; internment in Northern Ireland during the early 1970s became part of the problem, rather than the solution to terrorism troubles.

The second proposal – house arrests – has greater value, except in that it does not necessarily reduce the burden on security officials. An individual who has been placed under house arrest is not actually being dealt with; rather, he or she is being put in a very publicly visible ‘holding pattern’.

Similarly, excluding people from the UK – either through passport denial or exclusion orders – is not actually dealing with the challenge; it simply postpones a determination, and pushes the individual on to another country to be dealt with.

A proportion of the work managing this pool of 20,000 ‘lower-grade’ suspects will come under the contentious Prevent strategy of counterterrorism activity. And this raises another strand of debate to emerge from the Manchester atrocity: how to reform Prevent.

One aspect that should be undertaken is to separate out the different strands of the strategy. The work of managing dangerous offenders or suspects clearly needs to stay attached to the security realm, possibly through the creation of a new specifically developed and tailored service, modelled on the probation service.

Combining probation, welfare, police and intelligence, the new agency could be staffed by individuals who are each managing a specific case-load of former offenders or suspects.

Each case will require a different sort of engagement, but this may provide a way of both keeping an eye on such cases while also focusing on trying to get them on a different path.

A version of the Channel programme, which provides early support to individuals who are at risk of being drawn into terrorism, could be used; this will be a way of providing an individually tailored ‘light touch’ over-watch.

But other parts of the Prevent that are focused on more forward-looking efforts to steer people away from radical paths before they get on to them, should instead be moved firmly out of the criminal space.

Prevent is intended to be about keeping people away from ever getting to terrorism, and this means, among other measures, actually keeping them out of the criminal justice arena. Consequently, it would seem imperative that these programmes are not handled by a security department such as the Home Office.

Finally, there are some very understandable questions about the fact that the bomber was able to walk his device into a crowded space and kill so many. Most arenas nowadays are heavily guarded and people are subject to bag checks on entry.

Clearly, some additional thought must be given to reviewing entry and exit points to such sites, with the usual difficulties of agreeing where to draw the ultimate line of the security cordon.

Much work has gone into managing security in crowded spaces: the lessons learned need to be applied more rigorously and around the entire country. Sports events or concerts that by their very nature aim to be open and accessible will continue to pose a potential problem.

It is unlikely that this will be the last terrorist attack the UK faces. Coming during an election cycle, however, this incident offers an occasion for both introspection and new ideas as future governments continue to confront the challenge.

It has been a very busy week in the wake of the atrocity in Manchester. A few pieces coming over the next few days, but first up something for the New York Times looking at the intelligence spat between the US and UK around the sharing of information during counter-terrorism operations. More to come on the broader theme of the attack itself.

LONDON — The leaking of sensitive information about the investigation into Monday’s terrorist attack on the Manchester Arena, including forensic images of bomb apparatus, to United States media caused dismay and anger among British officials. The prime minister, Theresa May, went so far as to raise the issue directly with President Trump when they met at Thursday’s NATO conference in Brussels.

To modify George Bernard Shaw’s maxim, Britain and America appear to be two countries divided less by a common language than by common secrets. While British investigators jealously guard detailed information about their operations, seeking to run their leads to ground before they are exposed to view, their American counterparts seem more willing to put what they know directly into the public domain.

The Anglo-American security relationship has deep roots. Intelligence sharing and cooperation sits at its heart. Forged in history, it has deepened over time through a shared assessment of the threats they face around the world. A key part of this is countering terrorism, a mutual threat that our two countries work closely together to fight. And yet, in fighting it, they have different approaches.

A policeman in Manchester, England, on May 25.CreditJon Super/Agence France-Presse — Getty Images

The current tensions over Manchester are the latest public expression of an issue that has arisen before. In May 2012, British intelligence officials were exasperated when their role in an operation to disrupt a plot by Al Qaeda in the Arabian Peninsula — to repeat the 2009 underwear bomber plot with a more sophisticated device — was revealed. Before that, after the July 7, 2005 bombings in London, information about the nature of the bombs was leaked to the press by American sources early in the investigation. The chief of London’s Metropolitan Police at the time, Ian Blair, made a connection between that incident and the Manchester leak.

“I’m afraid it just reminds me exactly of what happened after 7/7,” he told the BBC, “when the U.S. published a complete picture of the way the bombs in 7/7 had been made up.” In 2005, he was concerned both about the impact of the images on victims of the bombing, and about how the disclosures could complicate the job of his officers investigating what had been the most serious Qaeda-inspired attack on Britain to date.

The frustrations have gone beyond the leaking of information being gathered after an attack. Back in 2006, British and American authorities disrupted the most extensive Qaeda plot they’d seen. Codenamed Operation Overt, the plan was to send a wave of up to eight suicide bombers on flights from Britain to North America using sophisticated liquid explosives they could smuggle on board. This is the root of the liquid ban on planes we still face today.

In close cooperation with their American counterparts, British authorities had been watching the cell, coordinated by a British Pakistani named Rashid Rauf who had risen up Al Qaeda’s ranks, for some time. They had discovered a bomb factory in East London where the group was making its devices. The moment was approaching to disrupt the plot, but the British authorities wanted to monitor it further to ensure they would sweep up the full network and have evidence that could be used in court.

But when the American authorities thought that someone connected to the network had managed to get onto a plane, they used their network in Pakistan to get Mr. Rauf picked up. This forced Britain’s hand. Such was the rush to action that unarmed surveillance officers had to step out of the shadows to grab the suspects before news spread about Mr. Rauf’s arrest.

One reason behind the divergence between British and American counterterrorism operations is that the British authorities prefer to watch and wait, gathering as much information as possible before moving into action. American agencies prefer a more aggressive approach to disrupting terrorist networks and plots. In part, this is a product of the legal system: Intelligence agencies in Britain closely guard the information they collect and do not usually allow it to be used in a court of law. This was visible during the subsequent trials of the Overt case, where prosecutors had to go three rounds with two hung juries before they were able to convict; one of the key figures was cleared and released notwithstanding his deeply suspicious links.

There are deeper cultural issues, too. This week, the government’s assessment of the threat of a further terrorist attack has led to the deployment of armed soldiers on the streets of Britain’s cities. This is something that would likely pass unnoticed in the United States, but it has caused great consternation here. British security officials are also uneasy about the number of American counterterrorism investigations that use undercover agents who often appear to act as agent provocateurs; in the British view, such operations would be regarded as entrapment by courts.

These tensions in the relationship seem to have intensified under the Trump administration. Some British counter-terrorism experts express concern that Mr. Trump’s rhetoric of aggressive confrontation may serve to bolster the very narrative of civilizational conflict the extremists use. The ties that bind Anglo-American intelligence cooperation are firm; the difficulty is how to maintain trust after this transatlantic spat. We face a common threat, and it would be dangerous to take for granted our common front in fighting it.

Raffaello Pantucci is the director of international security studies at the Royal United Services Institute in London, and the author of “We Love Death As You Love Life: Britain’s Suburban Terrorists.”

The successful use of a bomb is unusual among recent terror attacksCREDIT: JOEL GOODMAN/LNP

Terrorism has a predictable brutality to it. And yet, the idea of a bombing is something that still surprises us when it happens. The attack in Manchester in some ways appears a flashback to a different time when the terrorists we worried about detonated bombs, rather than using vehicles as rams or stabbing people. The reality is that terrorism’s only constant is its desire to shock and kill. For any group or ideology, the fundamental point is to make yourself heard as dramatically as possible. Groups and individuals will use whatever tools they have to gain that attention.

Making bombs that you know will reliably work is not as easy as it might sound. History is littered with attempted bomb-makers whose devices detonated too early or failed to go off. Unless you have had some training or practice, it is difficult to know for certain that you are making something that will go off exactly when you want it to.

There have been examples of lone bomb makers in the past, but they are rare. Anders Breivik, who killed 77 in Oslo in 2010, and David Copeland and Pavlo Lapshyn, who respectively launched one-man extreme right wing bombing campaigns in London and Birmingham, are examples. But in all cases, lone bomb makers choose to leave their devices behind rather than die in the detonation. This separates them from the Manchester bomber, though the degree to which we can conclude this means he acted alone is unclear.

Isil’s claim of responsibility would seem to strengthen the idea that the bomber was linked to someone. But care has to be paid to understand exactly what their claim means. On the one hand, it could be the group is merely claiming something to which it has a very loose link. The use of a bomb can also add confusion to the picture, especially when we consider that the majority of the incidents we have seen in Europe linked to the group of late have been stabbings or using vehicles to run down crowds. Yet this narrative assumes that the group is not keen to launch explosives attacks. This is incorrect – from the group’s perspective, anything that fulfills their goals of gaining attention and sowing terror is desirable.

The shift towards knives and cars was something that the group had encouraged in part as it realised that making bombs is difficult and prone to failure. Telling your aspirant warriors to keep it simple seems a more effective way to ensure success. One need only look at issues of the group’s magazine Rumiyah to see how rudimentary some of the forms of attack being promoted by Isil are.

Vehicles have been used as weapons, as in the Westminster attack earlier this year, for their ease and simplicityCREDIT: GEOFF PUGH FOR THE TELEGRAPH

But the key point to remember is that these groups, and Isil in particular, are not very discerning in their methodologies for terrorist attacks. Their aim is to cause chaos, draw attention to themselves and kill as many as they can. This brings attention to their cause and shows their commitment to their ideology. It is intended to sow divisions in our societies and strengthen the narrative of anger that is central to breathing life into their beliefs.

So whether they use a bomb and murder children, massacre people at airports, gun them down in concert halls, or stab elderly priests in their churches, they are getting their job done. And if we shout in horror at the methodology they employ, they simply brush this away by pointing to atrocities that they see happening around the world, and which they see as setting a precedent for violence.

The key issue from the rest of society’s perspective is to realise this is their deadly intent, and to ensure to not rise to the bait and do the group’s job for them. Terrorism’s only constant remains its perpetrators desire to shock and murder: the manner in which they do so is only secondary.

Raffaello Pantucci is Director of International Security Studies at RUSI and the author of We Love Death As You Love Life: Britain’s Suburban Terrorists